#include "toisegment.h"

#ifndef MAXINT
#define MAXINT 2147483647
#endif

static pthread_mutex_t cout_mutex = PTHREAD_MUTEX_INITIALIZER;
static void cout_lock() {pthread_mutex_lock(&cout_mutex);}
static void cout_unlock() {pthread_mutex_unlock(&cout_mutex);}
#define LOG(_xxx_) \
cout_lock(); \
_xxx_; \
cout_unlock();


/******************************/
/******* TOISegmented *********/
/******************************/

TOISegmented::TOISegmented(int bufsz, int maxseg) {
  master = new MasterView(bufsz, maxseg);
  setName("TOISegmented");
}

TOISegmented::TOISegmented(string nm, int bufsz, int maxseg) {
  master = new MasterView(bufsz, maxseg);
  setName(nm);
}

TOISegmented::~TOISegmented() {
  delete master;
}


void TOISegmented::addConsumer(TOIProcessor* p) {
  TOI::addConsumer(p);
  master->nConsumers = consumers.size();
}


double TOISegmented::getData(int i) { /* reader thread */
  return master->getData(i);
}

void TOISegmented::getData(int i, double& data, uint_8& flag) { /* reader thread */
  data = master->getData(i);
  flag = master->getFlag(i);
}

void TOISegmented::putData(int i, double value, uint_8 flag) { /* writer thread */
  master->putData(i, value, flag);
}

void TOISegmented::putDone() {
  master->putDone();
}

void TOISegmented::wontNeedBefore(int i) {  /* reader thread */
  master->getView()->wontNeedBefore(i);
}

TOI::DataStatus TOISegmented::isDataAvail(int i, int j) {
  // return master->getView()->isDataAvail(i, j);
  cout << "TOISegmented::isDataAvail unimplemented" << endl;
  throw PError("TOISegmented::isDataAvail unimplemented");
}

TOI::DataStatus TOISegmented::isDataAvail(int i) {
  return isDataAvail(i,i);
}

TOI::DataStatus TOISegmented::isDataAvailNL(int i, int j) {
  return isDataAvail(i,j);
}

void TOISegmented::waitForData(int iStart, int iEnd) {
  // get will wait...
}

void TOISegmented::waitForData(int i) {
  // get will wait...
}

void TOISegmented::waitForAnyData() {
  cout << "TOISegmented::waitForAnyData unimplemented" << endl;
  throw PError("TOISegmented::waitForAnyData unimplemented");
}

int TOISegmented::nextDataAvail(int iAfter) {
  cout << "TOISegmented::nextDataAvail" << endl;
  return iAfter+1;
}

bool TOISegmented::hasSomeData() {
  cout << "TOISegmented::hasSomeData" << endl;
  return true;
}

void TOISegmented::doPutData(int i, double value, uint_8 flag) {
  cout << "TOISegmented::doPutData unimplemented" << endl;
  throw PError("TOISegmented::doPutData unimplemented");
}

void TOISegmented::doGetData(int i, double& value, uint_8& flag) {
  cout << "TOISegmented::doGetData unimplemented" << endl;
  throw PError("TOISegmented::doGetData unimplemented");
}


/*******************************/
/******* BufferSegment *********/
/*******************************/

TOISegmented::BufferSegment::BufferSegment(int sz) {
  status     = NEW;
  bufferSize = sz;
  sn0        = -1;

  refcount   = 0;

  data       = new double[sz];
  flags     = new uint_8[sz];

  pthread_mutex_init(&refcount_mutex, NULL);
}

TOISegmented::BufferSegment::~BufferSegment() {
  if (refcount > 0) {
    throw(ForbiddenError("TOISegment : delete Buffer with refcount>0"));
  }
  delete[] data;
  delete[] flags;
  pthread_mutex_destroy(&refcount_mutex);
}

void TOISegmented::BufferSegment::putData(int sn, double d, uint_8 f) { 
  /* writer thread*/
  if (status == NEW) {
    status = WRITE;
    sn0 = sn;
  }
  if (status == COMMITTED) {
    throw(ForbiddenError("TOISegment : putData in committed buffer"));
  }
  checkInRange(sn);
  data[sn-sn0] = d;
  flags[sn-sn0] = f;
}

void TOISegmented::BufferSegment::incRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  refcount++;
  pthread_mutex_unlock(&refcount_mutex);
}

void TOISegmented::BufferSegment::decRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  int nrc = --refcount;
  pthread_mutex_unlock(&refcount_mutex);
  if (nrc<0)
    throw(ForbiddenError("TOISegment : buffer refcount < 0"));
}

int TOISegmented::BufferSegment::getRefCount() {
  pthread_mutex_lock(&refcount_mutex);
  int rc = refcount;
  pthread_mutex_unlock(&refcount_mutex);
  return rc;
}


/*******************************/
/********** BufferView *********/
/*******************************/

TOISegmented::BufferView::BufferView(MasterView* m) {
  master = m;
  sn0 = -1;
  segmentSize = m->segmentSize;
  firstNeeded = -1;
  waiting = false;
}

TOISegmented::BufferView::~BufferView() {
}

double TOISegmented::BufferView::getData(int sn) { /* Single-thread, reader thread*/
  ensure(sn);
  int seg = (sn-sn0)/segmentSize;
  return segments[seg]->getData(sn);
}

uint_8 TOISegmented::BufferView::getFlag(int sn) { /* Single-thread, reader thread */
  ensure(sn);
  int seg = (sn-sn0)/segmentSize;
  return segments[seg]->getFlag(sn);
}

void  TOISegmented::BufferView::ensure(int sn) { /* Single-thread, reader thread */
  if (sn < sn0) {
    LOG(cout << "TOISegmented::BufferView::ensure requested sample before first" << endl);
    LOG(cout << "sn " << sn << " sn0 " << sn0 << endl);
    abort();
  }

  if (sn0 < 0 ||
      sn >= sn0 + segmentSize*segments.size()) {
    LOG(cout << "BufferView " << hex << this << dec << ": read fault for " << sn << endl)
    sync();
    while (sn0<0 || sn >= sn0 + segmentSize*segments.size()) {
      wait();
      LOG(cout << "BufferView " << hex << this << dec << ": waiting for " << sn << endl)
      sync();
    }
    LOG(cout << "BufferView " << hex << this << dec << ": resuming for " << sn 
	<< " now data for " << sn0 << " - " << sn0 + segmentSize*segments.size() 
	<< " in " << segments.size() << " segments " << endl)
  }
}

void TOISegmented::BufferView::sync() { /* Single-thread, reader thread */
  master->updateView(this); // update me !
}

void TOISegmented::BufferView::wait() { /* reader thread */
  pthread_mutex_lock(&(master->read_wait_mutex));
  waiting = true;
  pthread_cond_wait(&(master->read_wait_condv), &(master->read_wait_mutex)); 
  waiting = false;
  pthread_mutex_unlock(&(master->read_wait_mutex));
}


void TOISegmented::BufferView::wontNeedBefore(int sn) { /* reader thread */
  if (sn > firstNeeded) {
    firstNeeded = sn;
  }
}


/*******************************/
/********** MasterView *********/
/*******************************/

TOISegmented::MasterView::MasterView(int bufsz, int maxseg) {
  currentSegment = NULL;
  maxSegments    = maxseg;
  segmentSize    = bufsz;
  sn0            = -1;
  nConsumers = 0;
  
  pthread_mutex_init(&views_mutex, NULL);
  pthread_mutex_init(&read_wait_mutex, NULL);
  pthread_cond_init(&write_wait_condv, NULL);
  pthread_cond_init(&read_wait_condv, NULL);
  pthread_key_create(&buffer_key, BufferDestroy);

  waitingOnWrite = false;
}

TOISegmented::MasterView::~MasterView() {
  pthread_mutex_destroy(&views_mutex);
  pthread_mutex_destroy(&read_wait_mutex);
  pthread_cond_destroy(&write_wait_condv);
  pthread_cond_destroy(&read_wait_condv);
  pthread_key_delete(buffer_key);

  // There should not be any BufferView left... Check ?
  
  // decrement count for segments ?
}

void TOISegmented::MasterView::putData(int sn, double data, uint_8 flags) { /* writer thread */
  if (sn0<0) {
    LOG(cout << "***MasterView::putData sn0<0" << endl)
    sn0=sn;
  }
  // can fit in current segment ?
  if (!(currentSegment != NULL &&
	sn >= currentSegment->sn0 &&
	sn < currentSegment->sn0 + currentSegment->bufferSize)) {
    LOG(cout << "MasterView::putData, need extend for " << sn << endl)
    nextSegment();
  }
  currentSegment->putData(sn, data, flags);
}

double TOISegmented::MasterView::getData(int sn) { /* reader thread */
  return getView()->getData(sn); /* thread-specific */
}

uint_8 TOISegmented::MasterView::getFlag(int sn) { /* reader thread */
  return getView()->getFlag(sn);
}

TOISegmented::BufferView* TOISegmented::MasterView::getView() { /* reader thread */
  BufferView* bv = (BufferView*) pthread_getspecific(buffer_key);
  if (bv == NULL) {
    bv = createView();
    LOG(cout << "creating new view " << hex << bv << dec << endl)
    pthread_setspecific(buffer_key, bv);
  }
  return bv;
}

void TOISegmented::MasterView::signalWaitingViews() { /* any thread */ /* views locked */
  pthread_mutex_lock(&read_wait_mutex);
  pthread_cond_broadcast(&read_wait_condv);
  pthread_mutex_unlock(&read_wait_mutex);
}

void TOISegmented::MasterView::signalWrite() { /* reader thread */ /* views locked */
  if (waitingOnWrite) {
    LOG(cout << "MasterView : signal for wait on write" << endl)
    pthread_cond_signal(&write_wait_condv); // only one thread can be sleeping
  }
}

void TOISegmented::MasterView::putDone() {
  nextSegment(); // cree un segment inutile, a nettoyer
}

void TOISegmented::MasterView::nextSegment() { /* writer thread */
  // The current segment, if any, is now committed. A new
  // blank buffer is allocated, if any.
  pthread_mutex_lock(&views_mutex);

  LOG(cout << "MasterView::nextSegment " 
      << segments.size()+1 << "/" << maxSegments << endl)

  if (currentSegment != NULL) {
    currentSegment->status = BufferSegment::COMMITTED;
    segments.push_back(currentSegment);
  }

  currentSegment = NULL;
  while (segments.size() >= maxSegments) {
    waitForCleaning();
  }

  currentSegment = new BufferSegment(segmentSize);
  signalWaitingViews(); // they can ask to be updated !!
  pthread_mutex_unlock(&views_mutex);
}

void TOISegmented::MasterView::waitForCleaning() { /* writer thread */ /* views locked */
  LOG(cout << "MasterView : write wait for clean for " << sn0 << endl)
  waitingOnWrite = true;
  checkDeadLock();
  pthread_cond_wait(&write_wait_condv, &views_mutex);
  LOG(cout << "MasterView : wait done" << endl)
}

TOISegmented::BufferView* TOISegmented::MasterView::createView() { /* reader thread */
  BufferView* bv =  new BufferView(this);
  pthread_mutex_lock(&views_mutex);
  allViews.insert(bv);
  pthread_mutex_unlock(&views_mutex);
  updateView(bv);
  return bv;
}

void TOISegmented::MasterView::updateView(BufferView* bv) { /* reader thread */
  pthread_mutex_lock(&views_mutex);

  int oldBegin = bv->sn0;
  int oldEnd   = bv->sn0 + bv->segmentSize * bv->segments.size();

  for (vector<BufferSegment*>::iterator i = bv->segments.begin();
       i != bv->segments.end(); i++) {
    (*i)->decRefCount();
  }
  
  bv->segments.clear();

  // utiliser firstNeeded de toutes les vues pour faire le menage chez
  // nous.
  
  // A condition que tous les consumers se soient fait connaitre...

  if (nConsumers == allViews.size()) {
    int firstNeeded = MAXINT;
    for (set<BufferView*>::iterator i = allViews.begin();
	 i != allViews.end(); i++) {
      if ((*i)->firstNeeded < firstNeeded) firstNeeded = (*i)->firstNeeded;
    }
    
    LOG(cout << "MasterView : firstNeeded = " << firstNeeded << endl);
      
    vector<BufferSegment*>::iterator j = segments.begin();
    bool clean = false;
    for (vector<BufferSegment*>::iterator i = segments.begin();
	 i != segments.end(); i++) { 
      if (((*i)->sn0+(*i)->bufferSize <= firstNeeded) && ((*i)->getRefCount() == 0)) {
	clean = true;
	j = i;
      } 
    }
    if (clean) {
      segments.erase(segments.begin(),j);
      sn0 = (*segments.begin())->sn0;
      LOG(cout << "MasterView : purged until " << sn0 << endl);
    }
  } else {
    LOG(cout << "MasterView : not yet all consumer thread known "<< allViews.size()
	<< "/" << nConsumers  << endl);
  }

  for (vector<BufferSegment*>::iterator i = segments.begin();
       i != segments.end(); i++) {
    if ( (*i)->sn0+(*i)->bufferSize > bv->firstNeeded ) {
      (*i)->incRefCount();
      bv->segments.push_back(*i);
    }
  }

  bv->sn0 = -1;
  int newEnd = -1;
  if (segments.size() > 0) {
    bv->sn0 = bv->segments[0]->sn0;
    newEnd = bv->sn0 + bv->segmentSize * bv->segments.size();
  }

  if (bv->sn0 > oldBegin) { // nettoyage de fait, reveiller le writer thread si besoin
    signalWrite();
  }

  LOG(cout << "sync for " << hex << bv << dec << " : "
      << oldBegin << " - " << oldEnd << "  -->  "
      << bv->sn0 << " - " << newEnd << endl);
  
  if (newEnd > oldEnd) { // Nouveautes, reveiller les reader threads si besoin
    signalWaitingViews();
  }
  pthread_mutex_unlock(&views_mutex);
}

void TOISegmented::MasterView::checkDeadLock() { /* views locked */
   // There is a possible deadlock if no view can free old segments
  // and we are waiting for write.

  // we need to record "wont need before" for each view, and 
  // signal deadlock if any view that needs first segment data is sleeping
  // while we are asleep

  pthread_mutex_lock(&read_wait_mutex);
  if (!waitingOnWrite) {
    pthread_mutex_unlock(&read_wait_mutex);
    return; // no problem, there is an active writer
  }

  // Is any sleeping view needing our first segment ?

  for (set<BufferView*>::iterator i=allViews.begin();
       i != allViews.end(); i++) {
    if ((*i)->waiting && (*i)->firstNeeded < sn0+segmentSize) {
      cout << "**** DEADLOCK detected ****" << endl;
      cout << "We are waiting on write (buffer is full)"<< endl;
      cout << "but a waiting reader still needs our first segment" << endl;
      cout << "restart with bigger buffers" << endl;
      abort();
    }
  }
  pthread_mutex_unlock(&read_wait_mutex);
}



void TOISegmented::MasterView::BufferDestroy(void* p) {
  BufferView* bv = (BufferView*) p;
  delete bv;
}